1. Field of the Invention
This invention pertains generally to video coding, and more particularly to transform unit (TU) encoding and decoding within high efficiency video coding standards.
2. Description of Related Art
In high efficiency video coding (HEVC), a coding unit (CU) may have variable sizes depending on video content toward achieving a desired coding efficiency. CUs typically include a luminance component, Y, and two chroma components, U and V. The size of U and V components relate to the number of samples, and can be the same or different from that of the Y component, as depends upon the video sampling format. These coding units may be split into smaller blocks for prediction or transform. In particular, each coding unit may be further partitioned into prediction units (PUs) and transform units (TUs). Prediction units (PU) can be thought of similarly to partitions described in other video coding standards, such as the H.264 standard. Transform units (TU) generally refer to a block of residual data to which a transform is applied when generating transform coefficients.
Transform unit (TU) coding within high efficiency video coding (HEVC), requires complex coding steps with significant processing overhead and generally comprise several steps including:
mode dependent coefficient scan (MDCS), last non-zero coefficient coding, significance map coding and nonzero coefficient level coding. These components vary at different transform unit (TU) sizes.
Accordingly, a need exists for simplifying the design of HEVC coding. The present invention fulfills that need as well as others, toward improving HEVC coding operations.